This invention relates generally to the field of methods and apparatus for pitting fruits of the drupe type. More particularly, it relates to apparatus for selectively torque pitting such fruits having sound pits and for automatically and selectively spoon pitting such fruit having split pits, irrespective of the order in which fruit having sound pits and fruit having split pits are presented to the pitting station.
The most common method and apparatus used in pitting fruits of the drupe type, such as peaches, apricots and the like, provide for torque pitting the fruit. In this technique, the fruit body halves are substantially bisected and the pit is gripped against rotation while the fruit body halves are rotated relative to and about an axis extending through the pit, thus twisting the fruit body halves free of the pit. However, it is not uncommon for some of the fruit presented to the pitting station to have unsound or split pits, this fruit being intermingled with other such fruit having sound pits. If the torque pitting technique is used with fruit having a split pit, generally all that is accomplished is the bisecting of the fruit and its split pit into two halves and then passing the fruit body halves with their attached pit halves onto subsequent stations where these fruit body halves must be repitted with a coring spoon to remove these split pit halves.
One seemingly obvious solution to the problem is to use a spoon pitting machine to cut a core which includes the split pit from each of the fruits presented, regardless of whether the fruit has a split or sound pit. However, since a spoon pitting machine must necessarily cut a core from each fruit at least as large as the largest pit anticipated, it necessarily removes some of the pulp, or meat, adjacent the pit in order that it may stay clear of the pit itself. This causes a loss of saleable fruit pulp from fruit having sound pits, which loss would not occur had torque pitting been used. Various compromise solutions to this problem have been attempted by canners. One such solution has been the provision of separate torque pitting and spoon pitting lines in the canneries, with batches of fruit suspected of having a high incidence of split pits being processed along the spoon pitting line and all other fruit being processed along the torque pitting line. This compromise has been unsatisfactory in its requirement for different sets of torque pitting and spoon pitting equipment, some of which may lie idle if fruit having split pits or sound pits is not available. Additionally, there likely will remain the requirement for spoon pitting the still substantial number of split pit fruit processed along the torque pitting line.
An improvement over the initial compromise may be found by using the convertible equipment similar to that disclosed in Brown U.S. Pat. No. 3,829,591 and in the further improved selective pitting apparatus of Spence U.S. Pat. No. 4,054,675. In the structure of the Spence patent a single pitting apparatus detects the presence of split or sound pits and adjusts the apparatus accordingly. Thus, with the Spence apparatus, fruit having sound pits may be torque pitted, to reduce the loss of available fruit pulp, while fruit having split pits would generally be spoon pitted, as required. By the provision of such selective apparatus the unnecessary and wasteful duplication of equipment may be reduced and a substantially higher yield of properly pitted fruit obtained. However, even when the Spence apparatus is in its spoon pitting mode, it requires that the fruit halves be rotated, as in torque pitting, through a full circle relative to a stationary coring knife and about an axis normal to the plane of the fruit suture. This rotation not only may tear the pulp of the fruit as it is rotated by the bisecting blade, but also necessarily cuts a generally spherical core far larger than the oblong pit. The rotation of the fruit halves also tends to cut from and sling away from the pitting area pieces of the fruit. These pieces of the fruit, which normally are quite acidic, are then flung into other parts of the processing apparatus, and have promoted rust and corrosion of other metal pieces, and have required additional cleaning of the pitting area.
In most of the automated pitting apparatus of the prior art, the apparatus operates cyclically, performing some predetermined sequence of steps regardless of whether a fruit is received from a preceding processing station into the pitting station or not. Such steps typically have included the actuation of the fruit body bisecting blades and actuation of the fruit body halve gripping elements. Such gripping elements have included deformable or deflectable fingers and also mutually opposed, inflatable elastic cups. A disadvantage of the prior art has been that such gripping apparatus customarily is actuated and may interfere with the fruit body bisecting and pit gripping apparatus when no fruit is presented to the pitting station during a given cycle of operations. Such an event can lead to premature wear and damage to either the fruit body gripping structure or the body bisecting and gripping structure of the pitter.